Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gi

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"r?call[\t ]+_(?!.*boot).*" test_str = (" 88811 000294 00 A0 A9 bclr.b _RCONbits,#5 ;,\n" " 88813 000296 00 00 07 call _vBootInitSerialBuffer ;\n" " 88815 000298 F0 0E 20 mov #239,w0 ;,\n" " 88816 00029a 00 00 07 rcall _vBootInitSerial_C1 ;\n" " 88818 00029c F0 0E 20 mov #239,w0 ;,\n" " 88819 00029e 00 00 07 rcall _vBootInitSerial_C2 ;\n" " 88821 0002a0 00 40 EB clr.b w0 ; tmp38\n" " 88822 0002a2 00 E0 B7 mov.b WREG,_gbTurnOnLED ; gbTurnOnLED\n" " 89049 00032e E0 0F 50 sub w0,#0,[w15] ; tmp56,\n" " 89050 Call the routine\n" " 89051 000330 00 00 3A bra nz,.L50 ;\n" " 89053 000332 10 C0 B3 mov.b #1,w0 ;,\n" " 89054 000334 00 00 07 rcall _memcpy ; <HIT>\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89054 000334 00 00 07 rcall _BxootGGashLED ; <HIT>\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89054 000334 00 00 07 rcall _BootFlashLED ;\n" " 89054 000334 00 00 07 call _ln ; <HIT>\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89054 000334 00 00 07 call _vBoootFlashLED ; <HIT>\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89054 000334 00 00 07 rcall _u8BootGGashLED ;\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89054 000334 00 00 07 rcall _u16bootGGashLED ;\n" " 89055 000336 00 00 37 bra .L50 ;\n" " 89056 .L49:\n" " 89058 000338 00 00 80 mov _gu16_50HzTimerTick,w0 ;") matches = re.finditer(regex, test_str, re.IGNORECASE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html